Early diagnosis and treatment of cancer greatly improve the likelihood of long-term survival and health. In Phase I, NanoScale Corporation and its partners at Kansas State University developed functionalized cancer-seeking "stealth" Fe/Fe3O4 core/shell nanoparticles, and demonstrated their feasibility for diagnosis of cancer by optical imaging. In Phase II, the NanoScale/KSU team will optimize the nanoparticles for diagnosis of breast cancer by fluorescence optical imaging, giving the surgeon an immediate technique for identifying the tumor margin. A maximum Tolerated Dose study, including a Repeat Dose phase, will evaluate toxicity in rats. An Ames test will evaluate mutagenic potential. Ex vivo studies with excised breast tumor specimens will determine the ability of the functionalized nanoparticles to improve margin identification. A Clinical Study Report will be prepared, and discussed with FDA personnel in a pre-IND meeting. Strategic alliances with recognized diagnostic/imaging companies will be established. NanoScale has extensive experience in synthesis, manufacture, and characterization of metal and metal oxide nanoparticles. Professors Stefan Bossmann and Deryl Troyer are internationally recognized for their accomplishments in synthesizing and evaluating anti-cancer compounds. Dr. Mark Cohen, surgical oncologist, is an expert in evaluating novel targeted therapies. Dr. Scott Weir has great experience in drug development and registration.